When you receive an HbA1c result, the percentage may feel difficult to connect with the blood sugar numbers you see on a glucose meter. This HbA1c to Average Glucose Calculator converts HbA1c into estimated average glucose, also called eAG, in both mg/dL and mmol/L.
I use this conversion when explaining laboratory results because it places HbA1c in more familiar glucose units. However, eAG is still an estimate. It does not show your current blood sugar, individual glucose spikes, low blood sugar episodes, or the full day-to-day pattern that may be seen with finger-stick testing or continuous glucose monitoring.
Written by: Dr. Albana Greca Sejdini, MD, MMedSc, Family Physician and Medical Author
Specialist medical review: Dr. Ruden Cakoni, MD, Endocrinologist
Last medically reviewed: July 2026
Enter your laboratory HbA1c result as a percentage or in mmol/mol. The calculator will estimate the average glucose associated with that result in mg/dL and mmol/L. HbA1c generally reflects glucose exposure over approximately the previous 2 to 3 months, with recent weeks influencing the result more than earlier weeks.
This calculation is educational. It cannot diagnose diabetes, determine whether your treatment is safe, or tell you to change insulin or diabetes medication.
Enter one HbA1c value. You may use either HbA1c percentage or IFCC mmol/mol.
Formula used:
eAG (mg/dL) = 28.7 × HbA1c (%) − 46.7
eAG (mmol/L) = eAG (mg/dL) ÷ 18
IFCC (mmol/mol) = 10.93 × HbA1c (%) − 23.50
This relationship comes from the international A1C-Derived Average Glucose study and the NGSP/IFCC standardization equations. Individual results may differ from the calculated estimate.
When I discuss HbA1c with patients, one of the most common misunderstandings is expecting the eAG number to match every glucose reading. It will not. A glucose meter shows one moment, while HbA1c reflects a much longer period.
I also remind patients that two people can have the same HbA1c but very different daily patterns. One person may have relatively stable glucose, while another may alternate between high and low readings. This is why I do not interpret HbA1c in isolation when meter or CGM information is available.
The chart below shows common conversions using the same standard relationship as the calculator. Values are rounded, so a laboratory report or another calculator may differ slightly.
| HbA1c (%) | HbA1c (mmol/mol) | Estimated average glucose (mg/dL) | Estimated average glucose (mmol/L) |
|---|---|---|---|
| 5.0% | 31 | 97 | 5.4 |
| 5.7% | 39 | 117 | 6.5 |
| 6.0% | 42 | 126 | 7.0 |
| 6.5% | 48 | 140 | 7.8 |
| 7.0% | 53 | 154 | 8.6 |
| 8.0% | 64 | 183 | 10.2 |
| 9.0% | 75 | 212 | 11.8 |
| 10.0% | 86 | 240 | 13.3 |
| 11.0% | 97 | 269 | 14.9 |
| 12.0% | 108 | 298 | 16.6 |
Estimated average glucose translates HbA1c into the same units commonly used by glucose meters. It may help you understand what an HbA1c percentage represents in everyday glucose language.
A laboratory measure of long-term glucose exposure, usually covering approximately 2 to 3 months.
A mathematical estimate calculated from HbA1c. It is not a separately measured glucose result.
Shows current glucose or detailed daily patterns, including timing, variability, highs, and lows.
HbA1c and eAG do not tell you whether your glucose was stable. They do not identify exactly when glucose was high, whether you had overnight lows, or how your blood sugar responded to a particular meal. For patients using insulin or medicines that can cause hypoglycemia, these details may be essential for safe treatment decisions.
For a broader explanation, read HbA1c Explained: What It Means and What Is a Good Level?
The categories below apply to an appropriately performed HbA1c test—not to the eAG number by itself. In a person without clear symptoms or unequivocal hyperglycemia, a result in the diabetes range generally requires confirmation with repeat or alternative testing.
| Laboratory HbA1c result | General diagnostic category | Important interpretation |
|---|---|---|
| Below 5.7% | Below the usual prediabetes threshold | This does not rule out every glucose problem, especially when symptoms or other test results are concerning. |
| 5.7% to 6.4% | Prediabetes range | Your doctor may review fasting glucose, risk factors, medications, and whether follow-up testing is needed. |
| 6.5% or higher | Diabetes range | Diagnosis usually requires confirmation unless there is unequivocal hyperglycemia or a clear clinical presentation. |
HbA1c is not the preferred test for diagnosing every form of diabetes. Different testing approaches are used in situations such as suspected type 1 diabetes, pregnancy and gestational diabetes, and some conditions affecting red blood cells or hemoglobin. Please discuss the correct diagnostic test with your healthcare professional.
There is no single HbA1c target that is safest for every person. A common goal for many nonpregnant adults with diabetes is around HbA1c below 7%, but this is not a universal prescription. Your target may be higher or lower depending on factors such as your age, diabetes type and duration, pregnancy status, medications, kidney or heart disease, risk of hypoglycemia, ability to recognize low blood sugar, and overall health.
A lower HbA1c is not automatically better if achieving it causes repeated or severe hypoglycemia. Do not change insulin, tablets, injectable medication, food intake, or exercise based only on this calculator.
A difference does not automatically mean that one result is wrong. I first look at what each number actually represents.
When there is a persistent or clinically important mismatch, take your laboratory report, meter log, and CGM report to your doctor. The safest response is to investigate the difference rather than adjusting medication from one number alone.
See a real patient-focused explanation in HbA1c 6.6% but normal finger-prick blood sugar readings.
The calculator can perform the mathematics correctly and still give a misleading clinical picture if the HbA1c result itself has been affected. Conditions that alter red blood cell lifespan, hemoglobin structure, or the laboratory method may produce a falsely high or falsely low HbA1c.
Examples that deserve medical review include:
Speak with your doctor if your HbA1c is unexpectedly high or low, especially when it does not match your measured glucose. Do not increase insulin or glucose-lowering medication solely to make the calculated eAG lower. If the HbA1c is falsely elevated, this could cause dangerous hypoglycemia.
For important medical decisions, use a result from an appropriately certified laboratory or qualified clinical testing service and review it with your clinician. Home HbA1c kits may be useful for personal tracking, but sample collection, storage, device quality, and user technique may affect the result. Confirm an unexpected home result before changing treatment.
For diagnosing diabetes, testing standards matter. A calculated eAG from a home test should never be used to diagnose yourself.
HbA1c is often checked about twice a year when diabetes is stable and treatment goals are being met. It may be checked approximately every 3 months when therapy has changed, glucose is not within the agreed target, or closer follow-up is needed. Your clinician may recommend a different schedule based on pregnancy, diabetes type, treatment, health conditions, and recent results.
There is little value in using this calculator every day with the same HbA1c number. Use it after receiving a new HbA1c result or when you need to understand a reported HbA1c in familiar glucose units.
HbA1c cannot tell you whether your blood sugar is dangerously high or low right now. If you feel unwell, have symptoms of hypoglycemia or severe hyperglycemia, are vomiting, have ketones, are confused, or have difficulty staying awake, check your current glucose if possible and follow your emergency or sick-day plan.
For immediate-number guidance, see Is My Blood Sugar Too High or Too Low? and Dangerous Blood Sugar Levels.